1. Field of the Invention
The invention relates broadly to what conventionally is known as a combustion process of the type used in piston-type internal combustion engines, as well as combustion chamber designs for such engines and arrangements for distributing fuel and air in the combustion chambers during engine operating cycles.
2. The Prior Art
The evolution of present day automotive gasoline and high speed diesel engines has not proceeded without its share of hereditary defects that have been transmitted to each successive generation of engine designs. Modern piston engines, while representing state of the art development concepts and embodying the most sophisticated refinements known to engine designers, are increasingly subject to disparagement for their polluting emissions and their insatiable appetite for easily combusted petroleum derivative fuels.
Piston-type internal combustion engines use a variable volume working chamber for carrying out cyclic conversion of chemical energy to thermal potential by reacting highly activated fuel (e.g. hydrocarbon, alcohol or ketone) with oxygen in a rapid, dissociative chain reaction process that quasi-instantaneously generates gaseous pressure from the released energy for driving a piston that in turn moves the work producing element of the engine. Products of the reaction, which reaction is conventionally termed combustion, are exhausted to atmosphere at the end of each cycle, and the process depends in large measure for its success upon the availability of fuels that can be rapidly reacted in the brief instant that the combustion chamber is at minimum volume after each fuel and air charge is placed in the working chamber of the engine and activated by rapid mechanical compression, with or without external ignition (e.g. spark or glow discharge).
Production of intermediate reaction products due to incomplete combustion or cracking of compounds at high pressures and temperatures are known sources of polluting emissions, and the requirement for smooth, stable firing, efficient high speed engines dictates the use of liquid or gaseous hydrocarbon fuels such as gasoline or diesel fuels, with various volatility improving and anti-knock additive compounds, depending upon the particular fuel and the compression ratio of the engine for which the fuel is intended. While alcohols and other fuels have been and still are undergoing active evaluation for use in modern internal combustion engines, gasoline and other liquid hydrocarbon fuels continue to constitute the major energy source for these engines.
The need to decrease the dependence of mankind upon natural petroleum resources as the source of engine fuels is now well recognized as is the need for more creative development in the field of internal combustion engines that can more efficiently extract energy from consumed fuel of any kind without producing undesirable polluting emissions. To this end, the prior art technology has been seen to propose various reaction cycles and combustion chamber designs for achieving clean, efficient operation of Otto, Diesel and combined cycle internal combustion engines. Unfortunately, it is submitted that the various prior art proposals have failed to take into account on a microscopic level, the time bounded nature of the enormous number of minute, discrete energy releasing bond breaking events that together constitute, on a macroscopic level, the combustion event of a work producing cycle that forms the basis of operation of a typical internal combustion engine. One observes that engines apparently have been designed up until now in accordance with the concept that, in order to satisfy the needs of rapid combustion in the short time available, fuels needed to be combusted virtually instantaneously, and the best way to achieve this, at least insofar as gasoline engines were concerned, was to place a homogeneous mixture of fuel and air in the combustion chamber with the proportion of fuel to air on the rich side of stoichiometric, depending upon power and efficiency requirements, and to ignite the mixture with a high energy spark discharge to obtain a rapid expansion effect from the generated thermal potential.
This basic theory has evolved along with various economy improving and pollution controlling concepts, including modern stratified engines where a rich mixture is compressed and ignited, and the heat generated from the initial combustion is used in turn to activate and combust a much leaner mixture in the combustion chamber in a multiphase combustion process.
Insofar as Diesel engine technology is concerned, distribution of fuel and air in the combustion chamber has been controlled to promote turbulence and thorough vaporization of liquid hydrocarbon fuel injected directly into the combustion chamber, and air reservoir chambers have also been used to insure the continuous supply of air for the combustion of the initial charge. All of these measures have been considered to promote complete combustion of the fuel with various levels of success.
It has even been recognized in Diesel engine technology that fuel-free air can be distributed to an air reservoir chamber that is in communication with the combustion chamber by carefully programming the injection of fuel into the combustion chamber so that it occurs after the air portion of each charge has been initially distributed in the combustion and reservoir chambers.
More recently, the inventor himself has proposed that more complete combustion in internal combustion engine could be achieved in a multi-phased combustion process termed a Heat Balanced Cycle wherein a portion of combustion air would be segregated from the combustion chamber during the compression stroke and be permitted to participate in the combustion reaction after initial activation resulting from the initial combustion after the pressure in the combustion chamber dropped below a predetermined level during the expansion phase. In this latest approach, in the Otto cycle version, fuel and air were distributed within the combustion chamber of the engine so that a portion of air alone could be placed in the combustion chamber during the intake stroke and then transferred to the reservoir chamber during the compression stroke, free of contamination with any substantial amount of fuel. Moreover, the air supply used to carry out the secondary combustion phase involved turbulent movement of an expanding air mass into the combustion chamber through a restriction. Certain difficulties in achieving stable combustion over various operating conditions were observed and it proved to be difficult to determine combustion chamber and reservoir chamber designs, as well as restriction parameters for every engine configuration. It was also found that segregation of air from the fuel in the reservoir chamber was difficult to achieve, particularly in Otto cycle engines. It was discovered that the quenching effect of excess air admitted into the combustion chamber during the latter stage of combustion was difficult to control in a predictable manner and the operating life of engine components was severely restricted in the combustion chamber area due to the inability to control the reaction rate and the mixture proportions. However, on the other hand, it was observed that the Heat Balanced Cycle offered theoretical improvements in reduction of peak pressures and temperatures in the combustion chamber of an engine modified to carry out the cycle, improvements in fuel economy, reduction of polluting emissions, and the possibility of multi-fuel capability for such engines. This invention has as an objective the provision of a process and apparatus capable of achieving the potential that was not attainable by the previous Heat Balanced Cycle.